Data cards include all types of financial cards such as credit, debit and A.T.M. cards as well as other cards that may contain non-financial data. Data cards are currently available in two types, magnetic strip cards and so-called smart cards. Imbedded within a smart card is an integrated circuit that includes a processor and memory for providing a variety of functions. One advantage of a smart card over a magnetic strip card is that the smart card contains all the intelligence necessary to complete a transaction locally at the transaction location. In contrast, transactions involving magnetic strip cards typically require verification via a transaction authorization service over a telephone network. Smart cards are expected to be used in an increasing range of transactions, including highway toll collection and dissemination of an individual's medical record information. Similar to a credit card, a smart card is typically limited to a single account.
If a consumer has several accounts he or she must have a different card for each account. U.S. Pat. No. 5,530,232 attempts to overcome this limitation by providing a smart card that may be used in connection with several different accounts. In this patent the electronic memory imbedded in the smart card is segmented for each account. Computer logic is used to ensure that different accounts are independently maintained. However, each time the cardholder uses the card, he or she would have to enter the account name and possibly some authorization code. In addition, as the number of accounts increases the corresponding amount of information that must be stored also increases. Accordingly, the required memory size, computing power, and dc power grows as the number of accounts per card grows.
It would therefore be desirable to provide a smart card that can support several different accounts while eliminating the need for complex user input and without unduly increasing the capacity of the individual electronic components embedded in the smart card.